Patient-Specific-Bone-Cutting Guidance Instruments And Methods

ABSTRACT

An orthopedic device for cutting or resurfacing an outer bone surface of a bone of a patient includes first and second guides. Each guide has a patient-specific surface preoperatively configured as a negative surface of a portion of the outer bone surface of the bone and a plurality of elongated slots. The elongated slots of the second guide are offset relative to the elongated slots of the first guide and configured for guiding a tool to resurface the outer bone surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/175,142 filed on Jul. 1, 2011. The disclosure of this application isincorporated by reference herein in its entirety.

INTRODUCTION

The present teachings provide various patient-specific guides and otherinstruments for guiding a cutting device to remove a small layer ofcartilage and/or bone of a joint of a patient or otherwise prepare thebone for a patient-specific resurfacing implant. The present teachingsalso provide patient-specific guides for guiding a tool to prepare abone for a non-custom implant. The patient-specific guides are designedand constructed preoperatively based on three-dimensional digital imagesof the patient's joint. The digital images of the patient's joint can bereconstructed from medical scans of the patient using commerciallyavailable CAD (Computer Aided Design) and/or other imaging software.

SUMMARY

The present teachings provide various orthopedic devices and associatedmethods for cutting or resurfacing an outer bone surface of a bone of apatient.

In some embodiments, the orthopedic device includes first and secondresurfacing guides. Each resurfacing guide has a patient-specificsurface preoperatively configured as a negative surface of a portion ofthe outer bone surface of the bone and a plurality of elongated slots.The elongated slots of the second guide are offset relative to theelongated slots of the first guide and configured for guiding a tool toresurface the outer bone surface.

In some embodiments, the orthopedic device includes a patient-specificannular frame preoperatively configured and contoured as a negativesurface of a corresponding contour of an outer bone surface of the boneand including an opening. A first patient-specific template isconfigured to be removably receivable in the opening of the annularframe. The first patient-specific template has a patient-specificsurface preoperatively configured as a negative surface of a portion ofthe outer bone surface. The first patient-specific template includes afirst plurality of elongated slots. A second patient-specific templatecan also be configured to be removably receivable in the opening of theannular frame. The second patient-specific template includes a secondplurality of elongated slots configured to be offset relative to thefirst plurality of elongated slots.

In a related method, the outer bone surface of the bone of the patientcan be resurfaced by positioning the first patient-specific guide on theouter bone surface and guiding a cutting portion of a cutting toolthrough each of the first plurality of elongated slots to resurface theouter bone surface under the first plurality of elongated slots. Thefirst patient-specific guide is removed from the outer bone surface andthe second patient-specific guide is positioned on the outer bonesurface to resurface the outer bone surface under the second pluralityof elongated slots such that the outer bone surface is contiguouslyresurfaced.

In some embodiments, the orthopedic device includes a patient-specificalignment guide having a patient-specific surface preoperativelyconfigured as a negative surface of a portion of an outer bone surfaceof the bone. The patient-specific alignment guide includes a guidingbore configured for inserting a reference pin into the bone. Theorthopedic device includes a resurfacing instrument having a removablecutting effector with a cutting surface and a guiding member. Theguiding member is connected to the resurfacing instrument and configuredto removably engage the reference pin and to reference the cuttingsurface to the outer bone surface for cutting or resurfacing after thepatient-specific alignment guide is removed. In some embodiments, thecutting surface is an abrading surface configured for removing articularcartilage from the outer bone surface. In some embodiments, the cuttingsurface is a patient-specific surface preoperatively configured as anegative surface of a portion of the outer bone surface of the bone ofthe patient. In other embodiments, the cutting surface is non-custom.

In a related method, the patient-specific surface of thepatient-specific alignment guide is mated on the outer bone surface andthe reference pin is inserted into the bone through the guiding bore ofthe patient-specific alignment guide. The patient-specific alignmentguide is removed without removing the reference pin. The resurfacinginstrument is coupled to the reference pin to register the resurfacinginstrument relative to the outer bone surface. The cutting effector iscoupled to the resurfacing instrument to resurface the outer bonesurface.

In some embodiments, the orthopedic device includes a patient-specificalignment guide having a patient-specific surface preoperativelyconfigured as a negative surface of a portion of an outer bone surfaceof a bone of a patient. The patient-specific alignment guide has aguiding bore configured for inserting a reference pin into the bone. Theorthopedic device also includes a patient-specific resurfacing guidehaving an opening configured to receive the reference pin after thepatient-specific alignment guide is removed from the bone. Thepatient-specific resurfacing guide has a patient-specific surfacepreoperatively configured as a negative surface of the outer bonesurface, and an elongated slot communicating with a side slot. Theorthopedic device includes a resurfacing tool having a shaft configuredto be movably coupled to the patient-specific resurfacing guide along asagittal plane of the bone. A patient-specific resurfacing member iscoupled perpendicularly to the shaft and configured to move along acoronal plane of the bone.

In some embodiments, the orthopedic device includes a physical bonemodel having a patient-specific surface configured to replicate an outerbone surface of a bone of a patient; and a reconfigurable resurfacinginstrument. The reconfigurable resurfacing instrument includes a movableand deformable resurfacing belt and a plurality of rollers extendingfrom adjustable elongated elements and pushing against the resurfacingbelt. The elongated elements operate to deform and set the resurfacingbelt to a shape that is negative surface of the patient-specific surfaceof the physical bone model, when the resurfacing belt is positioned onthe physical bone model.

In a related method, a three-dimensional digital image of a bone of apatient is prepared from medical scans of the patient. A physical bonemodel having an outer surface replicating an outer bone surface of thebone of the patient is prepared from the digital image of the bone. Areconfigurable resurfacing tool is set on the physical bone model toform a patient-specific resurfacing surface negative surface to theouter bone surface using the physical bone model.

Further areas of applicability of the present teachings will becomeapparent from the description provided hereinafter. It should beunderstood that the description and specific examples are intended forpurposes of illustration only and are not intended to limit the scope ofthe present teachings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is an environmental perspective view of a first patient-specificresurfacing guide according to the present teachings;

FIG. 1A is a detail of one embodiment of a patient-specific resurfacingguide according to the present teachings;

FIG. 1B is a detail of another embodiment of a patient-specificresurfacing guide according to the present teachings;

FIG. 2 is an environmental perspective view of a second patient-specificresurfacing guide according to the present teachings;

FIG. 2A is an environmental perspective view of a modularpatient-specific resurfacing guide according to the present teachings;

FIG. 3 is a perspective view of a resurfacing tool for use with thefirst and second patient-specific guides of FIGS. 1, 2 and 2A;

FIG. 4 is an environmental perspective view of a patient-specific guidefor installing a reference pin;

FIG. 5 is an environmental perspective view of the reference pin of FIG.4 referencing a guide of cutting tool relative to the bone according tothe present teachings;

FIG. 6A is an environmental view of a patient-specific cutting toolshown with the reference pin of FIG. 5 according to the presentteachings;

FIG. 6B is an environmental view of another cutting tool shown with thereference pin of FIG. 5 according to the present teachings;

FIG. 7 is an environmental view of a patient-specific guide for guidinga resurfacing tool according to the present teachings;

FIG. 8 is a plan view of a resurfacing tool for use with thepatient-specific guide of FIG. 7 according to the present teachings;

FIG. 9 is an environmental perepective view of the patient-specificguide of FIG. 7 shown with the resurfacing tool of FIG. 8 according tothe present teachings;

FIG. 10 is a front view of a digital display of an electronic deviceshowing a three-dimensional digital image of a bone according to thepresent teachings;

FIG. 11 is a perspective view of a physical bone model of a portion ofthe bone shown in FIG. 10 according to the present teachings;

FIG. 12 is a side view of a reconfigurable resurfacing instrument shownwith the bone model of FIG. 11 according to the present teachings; and

FIG. 13 is an environmental view of the reconfigured resurfacinginstrument of FIG. 12 shown with the bone imaged in FIG. 10 according tothe present teachings.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DESCRIPTION OF VARIOUS ASPECTS

The following description is merely exemplary in nature and is in no wayintended to limit the present teachings, applications, or uses. Forexample, although some of the present teachings are illustrated for aknee joint, the present teachings can be used for any other joint of apatient in joint arthroplasty.

The present teachings provide various patient-specific guides and otherinstruments for guiding a cutting device to remove a small layer ofcartilage and/or bone or otherwise prepare the bone for apatient-specific resurfacing implant. The present teachings also providepatient-specific guides for guiding a tool to prepare a bone for anon-custom implant. Various patient-specific guides, related tools andnon-custom devices are illustrated in FIGS. 1-13 and discussed in detailbelow.

Generally, patient-specific devices, such as patient-specific guides orother instruments and/or patient-specific implants can be designedpreoperatively using computer-assisted image methods based onthree-dimensional images of the patient's joint and/or adjacent anatomy,as reconstructed from MRI, CT, ultrasound, X-ray, or other medical scansof the patient. Various CAD programs and/or other software can beutilized for the three-dimensional image reconstruction of the anatomyfrom the medical scans of the patient, such as, for example, softwarecommercially available by Materialise USA, Plymouth, Mich.

Various pre-operative planning procedures and related patient-specificinstruments are disclosed in commonly assigned and co-pending U.S.patent application Ser. No. 11/756,057, filed May 31, 2007; U.S. patentapplication Ser. No. 11/971,390, filed on Jan. 9, 2008; U.S. patentapplication Ser. No. 12/025,414, filed on Feb. 4, 2008; U.S. patentapplication Ser. No. 12/039,849 filed on Feb. 29, 2008; U.S. patentapplication Ser. No. 12/103,824, filed Apr. 16, 2008; U.S. patentapplication Ser. No. 12/371,096, filed Feb. 13, 2009; U.S. patentapplication Ser. No. 12/483,807, filed Jun. 12, 2009; U.S. patentapplication Ser. No. 12/872,663, filed Aug. 31, 2010; U.S. patentapplication Ser. No. 12/973,214, filed Dec. 20, 2010; and U.S. patentapplication Ser. No. 12/978,069, filed Dec. 23, 2010. The disclosures ofthe above applications are incorporated herein by reference.

In the preoperative planning stage for joint reconstruction, resurfacingor replacement, a preoperative surgical plan is formulated for aspecific patient with optional interactive input from the patient'ssurgeon or other medical professional. Imaging data from medical scansof the relevant anatomy of the patient can be obtained at a medicalfacility or doctor's office, using any of the medical imaging methodsdiscussed above. The imaging data can include, for example, variousmedical scans of a relevant joint portion or other relevant portion ofthe patient's anatomy, as needed for joint or other anatomy modelingand, optionally, for determination of an implant alignment axis or forother alignment purposes. The imaging data thus obtained and otherassociated information can be used to construct a three-dimensionalcomputer (digital) image of the joint or other portion of the anatomy ofthe patient, such as, for example, the bones of a knee joint, hip joint,shoulder joint, etc. The three-dimensional digital image of thepatient's anatomy is used to formulate the preoperative surgical planfor the patient. The preoperative surgical plan includes the design andconstruction of patient-specific guides, instruments and/or implants orthe selection of non-custom implants and instruments according tosurgeon-selected methods of surgical preparation and implantation.

Generally, the patient-specific guides or other instruments(patient-specific devices, for short) of the present teachings arepreoperatively configured to match the surface of a bone (with orwithout cartilage) of a joint of a specific patient and are generallydesigned and preoperatively configured using computer modeling based onthe patient's reconstructed three-dimensional digital image of thepatient's pelvic anatomy. A patient-specific device has a boneengagement surface that is preoperatively configured to conforminglycontact and match the corresponding bone surface of the patient (with orwithout cartilage or other soft tissue), using the reconstructedthree-dimensional digital image of the patient's joint anatomy and thecomputer methods discussed above. In this respect, a patient-specificdevice can register and nestingly mate with the corresponding bonesurface (with or without articular cartilage) of the specific patient inonly one position. Accordingly, the patient-specific surface ispreoperatively configured as an inverse or mirror or negative or acomplementary surface of an outer surface of the corresponding bone,with or without cartilage.

The three-dimensional model of the patient's anatomy can be viewed on acomputer display or other electronic screen and can also be reproducedas a hard copy on film or other medium and viewed by direct or indirector backlight illumination. The model can be sized for viewing on anyappropriate screen size and may be cropped, rotated, etc., as selectedby the individual (e.g., the surgeon) viewing the screen.

The patient-specific devices can be manufactured by rapid prototypingmethods, such as stereolithography or other similar methods or by CNCmilling, or other automated or computer-controlled machining or roboticmethods. The patient-specific devices, the implants and optionally otherdisposable instruments can be packaged and sterilized, and forwarded ina patient- and/or surgeon-specific kit to the surgeon or the surgeon'smedical facility for the corresponding orthopedic procedure.

Referring to FIGS. 1 and 2, first and second patient-specificresurfacing guides 100A and 100B are illustrated for resurfacing anouter bone surface 83 of a bone 80 of a patient's joint. In thisexemplary illustration, the bone 80 is shown as a distal femur of a kneejoint, although the present teachings are applicable for resurfacing thebone of any other joint. Each patient-specific resurfacing guide 100A,100B, has a first or inner patient-specific surface 102A, 102B closelymating in a complementary manner and registering with the outer bonesurface 83 of the bone 80 only in one position. In other words, eachfirst patient-specific surface 102A, 102B is preoperatively configuredas an inverse or mirror or negative of the outer bone surface 83 of thebone 80 (with or without cartilage). Each patient-specific resurfacingguide 100A, 100B, has a second or outer surface 107A, 107B opposite tothe first patient-specific surface 102A, 102B. Referring to FIG. 1A, theouter surface 107A, 107B can be patient-specific and parallel to theinner patient-specific surface 102A, 102B for guiding a cutting (orresurfacing) tool 200, such as the tool shown in FIG. 3, to cut orresurface the bone 80 for a patient-specific implant, i.e., such thatthe resurfaced outer bone surface maintains its patient-specific shapeand still has the same negative surface. In some embodiments, the outersurface 107A, 107B can be non-custom, with planar surfaces for guidingthe cutting tool 200 to make planar resections for engaging the planaror multi-planar inner surface of a non-custom implant, as shown in FIG.1B. Each patient-specific resurfacing guide 100A, 100B includes acorresponding plurality of elongated slots 104A, 104B for guiding thecutting (or resurfacing) tool 200. The elongated slots 104B of thesecond patient-specific resurfacing guide 100B are offset and/oroverlapping relative to the elongated slots 104A of the firstpatient-specific resurfacing guide 100A, such that the entire outer bonesurface 83 of the bone 80 can be resurfaced contiguously for receivingan implant by using the first and second patient-specific resurfacingguides 100A, 100B consecutively.

Referring to FIGS. 1-3, the first patient-specific resurfacing guide100A can be registered on the bone 80 and the cutting tool 200 can beguided by the elongated slots 104A to remove cartilage (with or withoutremoving any underlying bone) under the elongated slots 104A from theouter bone surface 83, such as, for example, from the first and second(medial or lateral) femoral condyles 82, 84 of a distal femoral bone 80.After the outer bone surface 83 under the elongated slots 104A of thefirst patient-specific resurfacing guide 100A has been prepared, thefirst patient-specific resurfacing guide 100A can be removed and theremaining cartilage or unfinished outer bone surface 83 can be finishedor resurfaced either by free-hand use of the cutting tool 200 or othercutting tool or by using the second patient-specific resurfacing guide100B. The elongated slots 104B of the second patient-specificresurfacing guide 100B overlap the location of the elongated slots 104Aof the first patient-specific resurfacing guide 100A, such that theentire outer bone surface 83 can be prepared by sequentially using thecutting tool 200 through the corresponding elongated slots 104A, 104B ofthe first and second patient-specific resurfacing guides 100A, 100B. Thepatient-specific resurfacing guides 100A, 100B can also be secured onthe bone 80 with pins, K-wires or other fasteners (not shown).

Referring to FIG. 2A, in some embodiments, the patient-specificresurfacing guides can be modular and include of a patient-specificannular frame 100C having an opening 103 and one or morepatient-specific cutting templates 150, 150′ that can be received in theopening 103 and snap-fit or otherwise be removably coupled to thepatient-specific annular frame 100C. The patient-specific annular frame100C can be preoperatively contoured as a negative or mirror of thecorresponding contour (or curved surface strip) of a portion of theouter bone surface 83 of the bone 80 to be resurfaced. In someembodiments, the cutting template 150 can be designed as a partialcutting template to cover only a portion of the opening 103 (partialtemplate 150) and one or more additional partial templates 150′ can bedesigned to be received in the remainder of the opening 103. In theexemplary illustration of FIG. 2A, two partial cutting templates 150,150′ can be positioned one adjacent to the other to occupy the opening103, although a single cutting template can be also used for the entireopening 103. The patient-specific annular frame 100C can include a firstor inner patient-specific bone engagement surface 102C that can registerin only bone position on the outer bone surface 83 and an opposite(outer or second) surface 107C that can be either patient-specific andparallel to the inner patient-specific surface 102C ornon-patient-specific with planar or multiplanar portions as discussedabove. The patient-specific cutting templates 150, 150′ can also includecorresponding patient-specific bone engagement surface 152, 152′ thatregister in only bone position on the outer bone surface 83. Each of thepatient-specific surfaces 152, 152′ is preoperatively configured as aninverse or mirror or negative of outer bone surface 83, with or withoutcartilage.

The patient-specific cutting templates 150, 150′ can include a pluralityof elongated slots 154, 154′ for guiding a tool, such as the cuttingtool 200 shown in FIG. 3. Each patient-specific cutting template 150,150′ can be removed and replaced with a similar second template havingelongated slots that are offset and/or overlap relative to the slots154, 154′, as discussed above in connection with unitarypatient-specific resurfacing guides 100A, 100B. In some embodiments, aplurality (two or more) of partial cutting templates similar to thetemplates 150, 150′ can be used. In some embodiments, one or morepartial cutting templates 150, 150′ can slide in the medial-lateraldirection by a small offset, such that the outer bone surface 83 underthe corresponding partial cutting template 150, 150′ can be resurfacedfor receiving an implant without using additional partial templates withoffset elongated slots relative to the elongated slots 154, 154′. Aslidable partial cutting template can have a mediolateral dimension thatis sufficiently small such that it can slide relative to the outer bonesurface 83 while having a substantially patent-specific surface. Thepatient-specific annular frame 100C and, optionally, thepatient-specific cutting templates 150, 150′ can be secured on the bone80 with pins, K-wires or other fasteners (not shown).

Referring to FIG. 3, the cutting tool 200 can include a handle 202 and acutting portion 204, such as, for example, a burr or mill cutter. Thecutting tool 200 can include a depth stop 206 that can abut the outersurface 107A, 107B, opposite to the inner patient-specific surface 102A,102B of the patient-specific resurfacing guide 100A, 100B and limit thepenetration of the cutting portion 204 into the bone 80 through thecorresponding elongated slots 104A, 104B. The cutting portion 204 can bepreoperatively configured for removing cartilage and creating a finishedor resurfaced contoured surface of the bone 80 for receiving, forexample, a patient-specific implant. In other embodiments, the cuttingportion 204 can also be preoperatively configured to create a planarsurface for receiving a non-custom implant having a planar ormulti-planar bone-engaging surface.

Referring to FIGS. 4-6B, another bone preparation procedure andassociated instruments are illustrated according to the presentteachings. Briefly, a patient-specific alignment guide 300 is configuredfor registration (i.e., positionable by design in only one position) onthe outer bone surface 83 for installing a reference pin 410 on the bone80, as shown in FIG. 4. Patient-specific alignment guides forpositioning reference or alignment pins are also disclosed in theabove-referenced and incorporated herein patent applications and incommonly assigned and co-pending U.S. patent application Ser. No.12/955,361, filed Nov. 29, 2010, and incorporated herein by reference.The reference pin 410 can be used to guide a resurfacing instrument 400operable to remove cartilage and/or bone using a cutting surface 466 ofa cutting effector 460 of the resurfacing instrument 400. The cuttingsurface 466 can be patient-specific, as illustrated in FIG. 6A, forremoving cartilage and preparing the outer bone surface 83 for receivinga patient-specific implant. Alternatively, a cutting effector 460′ witha cutting surface 466′ can be coupled to the resurfacing instrument 400.The cutting effector 460′ can be non-custom and configured for removingcartilage and bone and preparing planar bone faces for a non-customimplant that has a corresponding planar or multi-planar bone engagingsurface.

More specifically, and with continued reference to FIGS. 4-6B, thepatient-specific alignment guide 300 can be configured preoperatively toinclude a patient-specific engagement surface 314 that is complementaryand made to closely conform and mate (as inverse, negative or mirrorsurface) with a portion of the patient's bone 80 (the anterior-distalouter bone surface 83 of the patient's femur 80 in the exemplaryillustration of FIG. 4) based on the pre-operative plan, as describedabove. The patient-specific alignment guide 300 can be lightweight andinclude a window/opening 315 and first and second distal guidingformations 312 a, 312 b defining guiding bores 313 for receivingfixation pins and/or guiding corresponding distal alignment pins (notshown). The patient-specific alignment guide 300 can also include eithera pair or, as shown in FIG. 4, a single anterior guiding formation 312 cdefining a guiding bore 313 for guiding corresponding anterior alignmentor reference pin 410 along an alignment direction A. The alignmentdirection A can be determined preoperatively for placing the cuttingsurface 466 of the resurfacing instrument 400 in a preoperativelydetermined position in reference to the outer bone surface 83 of thebone 80. Specifically, the reference pin 410 can be used as a guideafter the patient-specific alignment guide 300 has been removed, asshown in FIGS. 5, 6A and 6B. The patient-specific alignment guide 300can be secured on the bone 80 with pins, K-wires or other fasteners (notshown).

With continued reference to FIGS. 5, 6A and 6B, the resurfacinginstrument 400 can include a curved or angled guiding member 402 with adistal portion 404 that is preoperatively configured to be aligned alongthe alignment direction A when the distal portion 404 is coupled to thereference pin 410. A proximal portion 403 of the guiding member 402 canbe received in a bore 452 of a guide tube 450 or otherwise connected tothe guide tube 450. The guide tube 450 can be coupled to a holder 480 ofthe resurfacing instrument 400 using a connector 454. The connector 454can be integrally or removably coupled to the guide tube 450 and to theholder 480, such that when the guiding member 402 is coupled to thereference pin 410, the holder 480 is oriented to position the cuttingeffector 460 for resurfacing the outer bone surface 83 of the bone 80,as described above. The cutting effector 460 can be removably coupled tothe holder 480 with a shaft 468. The cutting effector 460 can be, forexample, a vibratory cutter, as illustrated in FIGS. 6A and 6B, or acutter with a burr or milling head or other type of cutting tool,including, for example, the resurfacing member 600 shown in FIG. 8, anddiscussed below in relation to another embodiment illustrated in FIGS.7-9. The cutting effector 460 can be operated through a connection to anexternal power source or to internal power source (battery).

In the illustrative embodiment of FIG. 6A, the cutting effector 460 caninclude a patient-specific support surface 464 preoperatively configuredto mirror (as a negative or inverse surface) the outer bone surface 83(or portion thereof) of the bone 80 to be resurfaced. Thepatient-specific support surface 464 can be a supporting surface coupledto grinding (or cutting) elements 462. In the patient-specificembodiment of FIG. 6A, the endpoints of the grinding elements 462 canform a patient-specific cutting surface 466 parallel to patient-specificsupport surface 464 and mirroring (negative or inverse surface) theouter bone surface 83 for removing cartilage. Although the grindingelements 462 are shown in exaggeration as teeth, in the embodiment ofFIG. 6A the grinding elements 462 can be grit-like and attached to thepatient-specific support surface 464. A suction device (not shown) canbe also attached to the holder 480 and provide suction to remove thecartilage particles or other resurfacing debris through a bore of theshaft 468.

Referring to FIG. 6B, the non-custom cutting effector 460′ can beremovably coupled to the holder 480 via a shaft 468′. The cuttingeffector 460′ can include a planar or piecewise planar (multi-planar)support surface 464′ that includes cutting elements 462′ in the form ofcutting teeth or cutting blade elements. The cutting elements 462′ canform a cutting surface 466′ parallel to the support surface 464′ and cancut planar surfaces through the bone 80 corresponding to the planes ofthe support surface 464′, removing both cartilage and bone material forpreparing the outer bone surface 83 for a non-custom implant havingplanar bone engaging interior faces.

Referring to FIGS. 7-9, another bone surface preparation procedure andassociated instruments according to the present teachings areillustrated. In this embodiment, the patient-specific alignment guide300 of FIG. 4 or a similar patient-specific alignment guide isregistered on the outer bone surface 83 of the bone 80 and used to guideand insert a reference pin 410 into the bone 80. The patent-specificalignment guide 300 is then removed, and the reference pin 410 is usedto guide and position a patient-specific resurfacing guide 500 on theouter bone surface 83, as shown in FIG. 7. The patient-specificresurfacing guide 500 can guide a resurfacing or cutting tool 650 toremove cartilage and/or bone from the outer bone surface 83 inpreparation for an implant, as shown in FIGS. 8 and 9 and discussedbelow.

More specifically and with continued reference to FIGS. 7-9, thepatient-specific resurfacing guide 500 has a hole or other opening 504for receiving the reference pin 410 and a patient-specific surface 502.The patient-specific surface 502 can be preoperatively configured tomirror (as a negative or inverse or complementary surface) and mate witha corresponding portion of the outer bone surface 83 of the bone 80. Thereference pin 410 facilitates the registration of the patient-specificresurfacing guide 500, such that the patient-specific resurfacing guide500 can have a small width relative to the width of the portion of theouter bone surface 83 to be resurfaced. Resurfacing can be effected oneach side of the patient-specific resurfacing guide 500 simultaneouslyor sequentially. For example, when the bone 80 is a distal femur, thepatient-specific resurfacing guide 500 can have a narrow width in themediolateral direction and track a narrow area between the first andsecond (medial or lateral) femoral condyles 82, 84, such that first andsecond femoral condyles 82, 84 can be exposed for either simultaneous orsequential resurfacing, as discussed below.

The patient-specific resurfacing guide 500 can include an externalelongated slot 520 along the sagittal plane of the bone 80. Theelongated slot 520 defines a pair of side openings 522 (one of the pairis hidden from view in FIG. 9). The elongated slot 520 can guide theresurfacing tool 650 to resurface the outer bone surface 83. Theresurfacing tool 650 can include a resurfacing member 600 and can bemovably coupled and guided by the elongated slot 520 such that theresurfacing member 600 can remove articular cartilage from the bone 80or otherwise prepare the outer bone surface 83 for receiving an implant.The resurfacing tool 650 can include a handle 653 and a shaft 652coupled to the handle 653. The shaft 652 can be received in the slot 520and move in the sagittal plane of the bone 80 (perpendicularly to thebone 80) along the slot 520. The resurfacing member 600 can be coupledto a rod or peg 654 that can pass through the side opening 522. The peg654 can be removably coupled to the shaft 652 and orientedperpendicularly to the shaft 652. The resurfacing member 600 can have aresurfacing (cutting or abrading) surface 602 that matches and engagesthe outer bone surface 83. The resurfacing surface 602 can bepatient-specific and configured during the preoperative plan of thepatient to conform in mirror-image fashion with the outer bone surface83 (with or without cartilage, depending on the procedure), asreconstructed in three-dimensional digital image from medical scans ofthe bone 80 of the patient.

The resurfacing member 600 can be coupled to the resurfacing tool 650 onone side of the patient-specific resurfacing guide 500 for resurfacing acorresponding side of the outer bone surface 83, such as the femoralcondyle 84 in the illustration of FIG. 9. The resurfacing member 600 canthen be removed and another resurfacing member 600 preoperativelyconfigured to be patient-specific to the outer bone surface 83 of theopposite side of the patient-specific resurfacing guide 500 (femoralcondyle 82) can be coupled to resurfacing tool 650 for completing theresurfacing of the outer bone surface 83. In some embodiments, a pair ofresurfacing members 600, one on each side of the patient-specificresurfacing guide 500, can be coupled simultaneously, rather thansequentially, to the resurfacing tool 650.

Referring to FIGS. 10-13, a method for creating preoperatively areconfigurable resurfacing or cutting instrument 800 is illustrated. Thereconfigurable resurfacing instrument 800 can be reconfigured or “set”for each patient to take a patient-specific resurfacing shape. Athree-dimensional digital image 80 i of the patient's bone 80 can bereconstructed from medical scans of the patient using commerciallyavailable imaging software, as discussed above. The digital image 80 ican be displayed on an electronic display 72 of a computer, computerterminal, portable or handheld tablet, mobile, cellular or otherelectronic device 70 equipped with a processor or communicating with aprocessor that runs the imaging software, as shown in FIG. 10. Thedigital image 80 i can have a digital outer surface 83 i correspondingto the outer bone surface 83, including, in the exemplary illustrationof FIG. 10, digital femoral condyle images 82 i, 84 i.

Referring to FIGS. 11-13, a patient-specific physical (not electronic)bone replica or model 700 can be created preoperatively from the digitalimage 80 i using, for example, rapid prototyping, stereolithography orother manufacturing methods. The physical bone model 700 can have anouter surface 702 that replicates (is a copy of) the outer bone surface83 (same as the digital outer surface 83 i). The physical bone model 700can be used as a setting surface to create and set an inverse shape on amovable and deformable resurfacing belt 880 of the reconfigurableresurfacing instrument 800 for removing cartilage from or otherwiseabrading the outer bone surface 83 of the bone 80, as shown in FIG. 13.

The reconfigurable resurfacing instrument 800 can include a handle 802and a frame 806 supporting the resurfacing belt 880 around pulleys 870extending from the frame 806. A shaft 804 can couple the handle 802 tothe frame 806. A plurality of rollers 822 can be connected to the frame806 with adjustable, retractable, telescopic or spring-biased elongatedelements 820, such as rods or bars. The adjustable elongated elements820 can be spring-loaded against the resurfacing belt 880, such thatwhen the resurfacing belt 880 is pushed against the outer surface 702 ofthe physical bone model 700, the lengths of the adjustable elongatedelements 820 can change to allow the resurfacing belt 880 to deform andtake the shape of a negative surface of the outer surface 702. Theadjustable elongated elements 820 can then be locked at thisconfiguration that sets the resurfacing belt 880 to a shape negative tothe shape of the outer surface 702 of the physical bone model 700 thatcorresponds to the patient's bone 80, as discussed above. Thereconfigurable resurfacing instrument 800 can be preoperativelyreconfigured for a different patient using a new physical bone model 700that is specific to the new patient. The resurfacing belt 880 isremovable and can also be sterilizable and reusable, or can be asingle-use disposable resurfacing belt 880.

In some embodiments, the resurfacing belt 880 can have a width (thedimension perpendicular to the side view of FIG. 12, or mediolateraldimension) sufficient to cover the entire outer surface 702 in FIG. 11,with the corresponding rollers 822 and elongated elements 820 arrangedin a three-dimensional array. In other embodiments, the resurfacing belt880 can have a width covering only a strip of the outer surface 702,with the corresponding rollers 822 and elongated elements 820 arrangedin a two-dimensional array. In yet other embodiments, the width of theresurfacing belt 880 can be sufficient to resurface one of the femoralcondyles (shown as 82 i, 84 i in the digital bone image 80 i of FIG.10). A narrow width of the resurfacing belt 880 can be selected forstability and ease of use. In such cases, the resurfacing belt 880 canalso be reconfigured intraoperatively, as needed or at the surgeon'sdiscretion, using the patient-specific bone model 700 for resurfacingother remaining portions of the outer bone surface 83. The physical bonemodel 700 can be included in the surgical kit for the specific patient,such that the reconfigurable resurfacing instrument 800 can bereconfigured intraoperatively to resurface additional portions of theouter bone surface 83 at the surgeon's discretion.

Referring to FIG. 13, in some embodiments the reconfigurable resurfacinginstrument 800 can be additionally referenced to the bone 80 using areference pin 810, which can be inserted into the bone 80 using apatient-specific alignment guide, such as the patient-specific alignmentguide 300 shown with reference pin 410 and discussed above in connectionwith FIG. 4. The reconfigurable resurfacing instrument 800 can beregistered to the reference pin 810 through a fixed or removableextension 830. Another reference pin 810 can also be placed in apatient-specific location and orientation in the physical bone model700. For example, a pin-receiving bore for receiving the reference pin810 can be incorporated in the physical bone model 700 in apreoperatively determined location and orientation. In some embodiments,instead of a resurfacing belt 880 other cutting elements can be used.For example, when the resurfacing belt 880 is not used, the rollers 822can be replaced by cutting wheels (also referenced 822) at the distalends of the elongated elements 820, such that the cutting wheels 822define a boundary surface (or envelope surface) that is negative to theouter bone surface 83. In this respect, a sufficient number of cuttingwheels 822 is used to contact and resurface the outer bone surface 83.

As discussed above, the present teachings provide variouspatient-specific guides and other instruments for guiding a cuttingdevice to remove a small layer of cartilage and/or bone or otherwiseprepare the bone for a patient-specific resurfacing implant or for anon-custom replacement implant. It is contemplated that elements andcomponents shown in one exemplary embodiment can also be used in anotherembodiment. Further, the methods and devices described herein can beused for a bone surface of any joint, including knee, hip, shoulder,etc. The various devices and methods of the present teachings can beused to resurface an articular bone surface by removing cartilage orcartilage and a layer of underlying bone in orthopedic resurfacingprocedures. Alternatively, the bone surface can be cut to remove boneand any overlying cartilage in preparation for implantation of anon-custom implant in orthopedic replacement procedures.

Example embodiments are provided so that this disclosure is thorough,and fully conveys the scope to those who are skilled in the art.Numerous specific details are set forth such as examples of specificcomponents, devices, and methods, to provide a thorough understanding ofembodiments of the present disclosure.

It will be apparent to those skilled in the art that specific detailsneed not be employed, that example embodiments may be embodied in manydifferent forms and that neither should be construed to limit the scopeof the disclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail. Accordingly, individual elements or features of aparticular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

What is claimed is:
 1. A method for cutting or resurfacing an outer bonesurface of a bone of a patient comprising: mating a patient-specificsurface of a patient-specific alignment guide on the outer bone surface,the patient-specific surface preoperatively configured as a negativesurface of the outer bone surface; inserting a reference pin into thebone through a guiding aperture of the patient-specific alignment guide;removing the patient-specific alignment guide without removing thereference pin; coupling a resurfacing instrument to the reference pin toregister the resurfacing instrument relative to the outer bone surface;and operating a cutting effector coupled to the resurfacing instrumentto resurface the outer bone surface.
 2. The method of claim 1, furthercomprising removing articular cartilage from the outer bone surfaceusing the cutting effector.
 3. The method of claim 2, wherein thecutting effector is configured with a patient-specific cutting surface.4. The method of claim 1, wherein the cutting effector is removable. 5.The method of claim 1, wherein coupling a resurfacing instrument to thereference pin includes coupling a guiding member to the reference pinand engaging the guiding member with a guide tube carrying the cuttingeffector.
 6. The method of claim 5, further comprising coupling a distalportion of the guiding member to the reference pin and coupling aproximal portion of the guiding member to the guide tube where theguiding member includes an angled portion between the proximal anddistal portions so that upon engaging the guide tube to the proximalportion of the guiding member, with the cutting effector is positionedat a patient-specific location.
 7. The method of claim 1, furthercomprising vibrating the cutting effector to remove articular cartilagefrom the outer bone surface.
 8. The method of claim 1, wherein operatingthe cutting effector further includes operating the cutting effectorhaving a patient-specific cutting surface to form a patient-specificcutting surface mirroring the outer bone surface to remove cartilage. 9.The method of claim 1, further comprising operating the cutting effectorcoupled to the resurfacing instrument to resurface the outer bonesurface of a distal femur.
 10. A method for cutting and resurfacing anouter bone surface of a bone of a patient, comprising: positioning areference pin in a preoperatively determined alignment directionrelative to the outer bone surface; coupling a first portion of aresurfacing instrument to the alignment pin in a position configured tobe aligned along the alignment direction; coupling a second portion ofthe resurfacing instrument to the first portion of the resurfacinginstrument to position a cutting effector carried by the second portionin a preoperatively determined position relative to the outer bonesurface; and operating the cutting effector coupled to the secondportion of the resurfacing instrument to resurface the outer bonesurface.
 11. The method of claim 10, further comprising removingarticular cartilage from the outer bone surface using the cuttingeffector.
 12. The method of claim 10, wherein the cutting effector isconfigured with a patient-specific cutting surface.
 13. The method ofclaim 10, wherein the cutting effector is removable.
 14. The method ofclaim 10, wherein coupling the second portion of the resurfacinginstrument to the first portion includes receiving a proximal portion ofthe first portion of the resurfacing instrument within a guide tube ofthe second portion of the resurfacing instrument.
 15. The method ofclaim 10, further comprising vibrating the cutting effector to removearticular cartilage from the outer bone surface.
 16. The method of claim10, further comprising operating the cutting effector coupled to theresurfacing instrument to resurface the outer bone surface of a distalfemur.
 17. The method of claim 10, wherein positioning the reference pinfurther includes mating a patient-specific surface of a patient-specificalignment guide on the outer bone surface and inserting the referencepin into the bone through a guiding aperture of the patient-specificalignment guide.
 18. The method of claim 17, further including removingthe patient-specific alignment guide without removing the reference pin.19. A method for cutting or resurfacing an outer bone surface of a boneof a patient, comprising: mating a patient-specific surface of apatient-specific alignment guide on the outer bone surface, thepatient-specific surface preoperatively configured as a negative surfaceof the outer bone surface; inserting a reference pin into the bonethrough a guiding aperture of the patient-specific alignment guide;removing the patient-specific alignment guide without removing thereference pin; coupling a guiding member to the reference pin; couplinga guide tube carrying a cutting effector over the guiding member toposition the cutting effector at a preoperatively determinedpatient-specific position; and operating the cutting effector toresurface the outer bone surface.
 20. The method of claim 19, furthercomprising removing articular cartilage from the outer bone surfaceusing a patient-specific cutting surface of the cutting effector.